Résumé
Arsenic (As) is a toxic element commonly found in mining sites. Removal of As from Acid Mine Drainages (AMD) can be obtained in anaerobic bioreactors thanks to sulfate-reducing bacteria (SRB) through the precipitation of arsenic sulfide. The present study aimed to develop the sulfate-reducing anaerobic step of a bioremediation scheme to treat AMD rich in As, zinc (Zn) and iron (Fe). Column bioreactors worked in series, with differential supply of organic substrates, i.e. yeast extract and glycerol. This strategy allowed to modulate pH and to efficiently precipitate As and Zn in the columns, although it was not possible to selectively recover Zn alone. Most part of the Fe remained in solution, and was treated downstream by oxidation, allowing the co-precipitation of residual As. The SRB biotreatment is currently up-scaled and will be tested on site.